Treating or polishing apparatus



April 7, 1959 1.. 3. SlMJlAN TREATING OR POLISHING APPARATUS Filed Jan. 3. 1956 FIG.2

AMPLIFIER FIG. 3

O A.C.

LUTHER G. SIMJIAN INVENTOR ATTORNEY United States Patent TREATING OR POLISHING APPARATUS Luther G. Simjian, Greenwich, Conn., assignor to The Reflectone Corporation, Stamford, Conn., a corporation of Connecticut Application January 3, 1956, Serial No. 557,055

2 Claims. (Cl. 51-7) This invention relates to a treating or polishing apparatus for polishing surfaces of objects immersed in a container. It has particular reference to a polishing means which can be employed to polish the surface of articles which are formed with reentrant cavities and other surfaces which are ditficult to polish by the usual polishing means. The invention described herein is an improvement over the devices described and claimed in US. Patents 2,735,231, and 2,735,232, issued February 21, 1956.

Polishing is generally done with a bufling wheel which is run at high speed and has been impregnated with a polishing compound. It is well known that such a device gives fast and satisfactory results on flat and convex surfaces. Concave surfaces, however, are more difficult to polish with a butfing wheel and small holes and cavities cannot be handled at all with this polishing means. The present invention can be used to polish any sort of surface including plane surfaces, holes, and other cavities. No mechanical motion is used exterior to the container which holds the object to be polished. A stream of abrasive particles within the container is moved in varying directions to effect high speed impact on the surface to be polished. The abrasive particles are magnetic and are controlled in their motion by one or more magnetic fields. In order to give mobility, the magnetic particles are suspended in a liquid which may be a light oil.

One of the objects of this invention is to provide an improved treating or polishing device which avoids one or more of the disadvantages and limitations of prior art arrangements.

Another object of the invention is to polish objects having small cavities.

Another object of the invention is to polish complex structures with complete safety to the operator.

Another object of the invention is to polish an object without the aid of mechanical motion external to the polishing bath.

Another object of the invention is to provide a polishing operation which is automatic and does not require the supervision of a trained operator.

One feature of the invention includes a non-magnetic container which holds a mixture comprising magnetic particles and a liquid. Electromagnetic means are provided for imparting a polydirectional motion to the particles. The object to be polished is positioned within the container and the electromagnetic means is supplied with electric power which causes a recurrent impact of the particles on the surface of the object.

Another feature of the invention is an electric control means external of the container which provides a cyclic change of the electric current supplied to the electromagnetic means.

Another feature of the invention is the combination of a direct current magnetic field and an alternating current field to increase the variations of movements of the magnetic particles.

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For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

Fig. 1 is a cross sectional view of one embodiment of the invention which includes two air-cored coils.

Fig. 2 is a cross sectional drawing showing two iron cored coils and an electronic switching means for varying the current in the coils.

Fig. 3 is a cross sectional drawing which shows how two electromagnetic fields may be combined.

Referring now to Fig. l a container 10 supports an object 11 which is to be polished. Within the container is a mixture 12 of magnetic abrasive particles and a liquid. The abrasive particles may be small particles of steel or any other paramagnetic material and the liquid may be water, a light oil, or any other suitable liquid which will lend suspension to the particles. At each end of the container 10 magnetic coils 13 and 14 are mounted and are connected to a source of electric power through a switching device 15. It has been found in practice that either alternating or direct current power may be used.

The switching device 15 includes a double pair of contacts 16 and a cam 17, run by a motor 18, which controls the middle contact point and oscillates it so that it makes alternate contact with the outside points to send power into each coil 13 and 14 in alternative sequence. The mixture 12 is illustrated in Fig. 1 as a mixture containing considerable consistency and piled at one side of the container after having been directed to that position by a current incoil 13. When the device is in operation and current is switched from one coil to the other in rapid succession, the mixture is given an oscillating motion, travelling from one side of the container to the other and striking all sides of the object 11. The consistency of the mixture may be varied over a wide range for various types of polishing action. It will be obvious that if the object 11 is a hollow cylinder with the axis of the hole coinciding with the axis of the coils, the inside of the hollow cylinder will be subjected to the polishing action to the same degree as the outside surface.

The alternate arrangement shown in Fig. 2 includes cores 20 and 21 partly surrounded by electromagnetic coils 13 and 14. The action is the same as before but the efiiciency is considerably increased. In this arrangement no moving contacts are used but instead a multivibrator circuit 22 is employed to deliver a series of sharp pulses over conductors 19 to a power amplifier 23 which amplifies the pulses and directs them to coils 13 and 14 in alternate sequence. The multivibrator circuit includes a double triode electron discharge device 24, this type of circuit being well known to electronic engineers. The power amplifier 23 may comprise two single stage amplifiers with coils 13 and 14 connected to the output circuits. This type of circuit is also well known and is described in many of the electronic handbooks now available. The operation of the device shown in Fig. 2 is the same as that shown in Fig. 1 except that there are no make and break contacts, no sparking, and no mechanical movement whatever except the movement of the abrasive particles.

The arrangement shown in Fig. 3 includes the container 10, the object 11, coils 13 and 14, and an additional coil 25 placed at right angles to the other coils. In this arrangement direct current power is supplied in alternate sequence to the end coils 13 and 14 as before, but a steady source of high frequency alternating current is connected to coil 25. The superposition of the alternating current field on the pulsed direct current fields imparts an undulatory motion to the magnetic particles as they travel from one side of the container to the other. This motion may be generally illustrated by the arrow 26.

In Fig. 3 an alternate switching arrangement is used which includes arelay type winding 27 controlling a vibrating reed 28 connected to a spring 30. This device operatesin I the same manner as the ordinary hell or buzzer and shifts the electric power from coil 13 to coil 14 through contacts 31.

While there have been described certain embodiments of the instant invention, it will be apparent to those skilled in the art that various other modifications may he made without departing from the spirit of the present invention which should be limited only by the scope of the appendedclairns.

I claim:

1, A polishing apparatus for an object positioned within a non-magnetic container comprising, a mixture of abrasive, para-magnetic particles and a liquid in said containerielectromagnetic means secured in fixed relationship to said container for creating a magnetic force within the container which moves the magnetic particles, and a switching circuit which applies power to said electromagnetic means in a cyclic'imanner.

2. A polishing apparatus for an object positioned within a non-magnetic container comprising, a mixture of discrete magnetic abrasive particles and a liquid in said container, electromagnetic means-secured in fixed relationship to said container for creating a magnetic force Within the container which moves the magnetic particles, and a-switching circuit including cam-operated contacts which applies power to said electromagnetic means in a cyclic manner.

References (Iited in the file of this patent UNITED STATES PATENTS 2,735,231 Simjian Fflb. 21, 1956 2,735,232 Sirnjian 21, 1956 -.-'.-*.-'.-f:' ""f'Z p 93 2,796,702 June 25, 1957 

